VB.Net is good language. Worst part of it is the name, which people associate with old VB and think that the .Net one is inferior language compared to C# for example.
Learning a new language is often fun, but it can be a bit pointless. Differences between Jave, VB.Net, C# and C/C++ are not that big after all. If you would try completely different thing, like functional language as kraflab said, you would probably pick up some new skills.
It might be a good idea to dig around internet a bit and see what kind of programming concepts there are, pick one that sounds interesting and read a bit more about it. If it sounds good, try it in your game and see how it feels like. Rinse and repeat as often as you feel like.
Even better is if you have a specific problem with your code and you want to find a solution to it. Want to make your programs more loosely coupled? See if you can use dependency injection to solve it (Unity is a free library for that for example). Want to write code that is easier to maintain? See if your local library has a book about design patterns or designing software in general. Want to try writing automated tests? Play around with NUnit and NSubstitute and see what you can do with them.
You can do things in hard way (all by yourself, learning from your mistakes and trying to come up with better ways of doing things), or you can stand on shoulders of giants and learn what others have done and build on that. Both can be fun, but latter one is much, much faster.
